1. Field of the Invention
The present invention relates to a driving method for a plasma display panel and a plasma display device.
2. Description of the Related Art
Up until now, display devices that selectively discharge plural discharge cells to display an image have been known. Examples of the display devices include a plasma display device disclosed in Patent Document 1 that has a display panel including plural discharge cells, a first driving unit that applies a driving pulse to a selected one of the discharge cells of the display panel to generate a first discharge, and a second driving unit that increases, after the voltage of the driving pulse decreases with the generation of the first discharge to weaken at least the first discharge, the voltage of the driving pulse again to generate a second discharge in succession to the first discharge.
In such a plasma display device, only a minimum power required for generating the discharge is input at the time of the first discharge. Therefore, the saturation of ultraviolet rays is alleviated by current limitation from the instant at which the first discharge starts weakening, which results in an improvement in luminous efficiency of the first discharge. As a result, the first discharge having high luminous efficiency as well as the second discharge is performed in all discharge cells to be lit. Accordingly, the luminous efficiency of all the discharge cells to be lit can be improved.
However, Patent Document 1 does not disclose a driving method in which the driving pulses that generate the first and second discharges are consecutively generated.
Meanwhile, according to a general driving method in which a discharge is generated once by one driving pulse to make discharge cells emit light, a high-voltage pulse is applied in a short period of time. Therefore, the discharge generated at this time is strong, which ensures sufficient amounts of wall charges in the discharge cells after the generation of the discharge. Accordingly, after this, it is possible to perform the second discharge described in Patent Document 1. However, according to the driving method described in Patent Document 1 in which the discharges are generated twice by one driving pulse, the strength of the discharges is weakened. As a result, the amount of wall charges in the discharge cells after the generation of the discharge is reduced. Therefore, even if other driving pulses that generate the discharges twice are consecutively applied right after the generation of the initial two discharges, the first discharge at the time of the subsequent two discharges is not properly generated. That is, the subsequent two discharges may not be generated. In other words, it is not possible to consecutively generate the voltage waveforms of the driving pulses having two voltage peaks.    Patent Document 1: JP-A-2002-6805